The long term goals for this work is to create a gene delivery vector that is efficient and safe for use in animals and people. The application potential for this vector technology includes human gene therapy and rapid production of genetically modified animals (e.g., therapeutic protein production, agriculture improvement, more relevant disease models, etc.). This vector technology enables targeted, in-animal gene delivery using a homologous recombination mechanism. As such, the concerns regarding genetic damage through random integration may be alleviated using this technology. In order for this technology to be viable for all of the possible applications, all of the integrations must be homologous (no random integration), the vector must integrate into most, if not all cell- and tissue-types in the animal, and the integration frequency must be high enough to obtain therapeutic effects. To date, we have limited observations that the proposed vector integrates homologously into the genomes of mice and rats. This project is to test what fraction of the integrations are homologous vs. random and what is the frequency for both homologous and random integrations. Specifically, we will examine the vector's ability to create a small and large deletion, deliver an exogenous gene, and fix a mutant gene. These vector constructs will be examined in both male and female mice through two different administration routes to determine the frequency and distribution of homologous and random integration. Furthermore, it will be determined whether multiple administrations of the vector construct increase the frequency of integration. The results of these experiments will be assessed using standard techniques at the molecular and functional levels. These results will be the basis for deciding whether this technology shows promise to continue testing in larger animals and eventually people.